Cigarette-making machinery

ABSTRACT

The invention is concerned with an apparatus and a method for the treatment of cut tobacco in a cigarette-making machine in which a stream of tobacco strands carried in a stream of air is subjected to microwave-radiation energy by passing it through a radiation chamber. Suitably, the wavelength of the microwave energy is in the range from 10 to 100 cms. and the stream of air carrying the tobacco is directed through the chamber at a substantial distance from the chamber walls where the energy level is low. The path of the tobacco strands through the chamber is defined by a pair of confronting end walls having straight inlet and outlet portions at their ends, and an arcuate portion therebetween that is convex toward a wave-guide that terminates in an outlet communicating with the interior of the chamber. The straight portions serve as microwave-retaining filters and the confronting walls are transparent to the passing of microwaves therethrough. A rotating fan is positioned to the passing of microwaves therethrough. A rotating fan is positioned in the chamber between the confronting walls and the energy inlet and serves to cool the adjacent arcuate wall. Tobacco leaving the chamber is formed into a filler stream and into a rod from which cigarettes may be cut.

United States Patent Russell 1 May 23, 1972 [54] CIGARETTE-MAKINGMACHINERY Primary Examiner-Joseph S. Reich [72] Inventor: erick RussellSouthampton England Attorney-Kane, Dalsimer, Kane, Sullivan and Kurucz[73] Assignee: Brown and Williamson Tobacco Corporation, Louisville, Ky.ABSTRACT I [22] Filed: Feb, 19, 1970 The invention is concerned with anapparatus and a method for the treatment of cut tobacco in acigarette-making [21] Appl' 12,642 machine in which a stream of tobaccostrands carried in a stream of air is subjected to microwave-radiationenergy by 30 F re A a m it passing it through a radiation chamber.Suitably, the I 1 o is ppuca on y Data wavelength of the microwaveenergy is in the range from to Feb. 27, 1969 Great Britain ..10,509/69100 cms. and the stream of air carrying the tobacco is directed throughthe chamber at a substantial distance from the [52] US. CL.......131/l10, 131/121, 131/84 B Chamber walls where the energy level islow. The path of the [51] Int. Cl. ..A24b 9/00, A24c 5/14 tobaccostrands through the chamber is defined by a pair of [58] Field at Search..131/1 10, 121, 84, 84 B, 84 C, confr n ng en w l having str g nl n lep r ons 131/21, 21 B, 21 A, 140 P at their ends, and an arcuate portiontherebetween that is convex toward a wave-guide that terminates in anoutlet commu- [56] References Ci d nicating with the interior of thechamber. The straight portions serve as microwave-retaining filters andthe confronting UNITED STATES PATENTS walls are transparent to thepassing of microwaves therethrough. A rotating fan is positioned to thepassing of g i a'j microwaves therethrough. A rotating fan is positionedin the 3494722 M1970 a e chamber between the confronting walls and theenergy inlet 3255763 6 1966 131/121 x and serves to cool the adjacentarcuate wall. Tobacco leaving l 1 3 ll 12] X the chamber is formed intoa filler stream and into a rod from 2,222,634 11/1940 Sm1th......131/121 UX which cigarettes may be cm 3,019,793 2/1962 Labb........131/110 X 2,497,501 2/1950 Himmel et a1 ..13l/121 X 9 Claims, 3Drawing Figures 1:! 72 1 I i 1 w 73 O ?ATENTE[]MAY23'I972 3,664,351

SHEET 2 UF 2 INVENTOR FREDERKLK RU SSELL CIGARETTE-MAKING MACHINERY Thisinvention concerns improvements relating to cigarettemaking machineryand particularly to machines in which the cut tobacco is delivered tothe forming mechanism by an air stream.

In the conventional manufacture of continuous tobacco rods, it is wellknown that during the forming process, and particularly in the gamiture,some physical degradation of the tobacco strands occurs. Thisdegradation can be reduced if the moisture content or the temperature ofthe tobacco, or both, can be raised, so increasing the pliability of thestrands. While the moisture content can be raised quite readily,cigarettes are then produced which have an undesirably high moisturecontent for subsequent packing operations and inconvenient delays areincurred while the moisture-content of the cigarettes is adjusted to asuitable value for packing. Heating the tobacco has been found to betechnically difficult, since the provision of sufficient heat to produceany marked rise in the temperature of the rapidly moving stream oftobacco strands involves considerable problems of heat transfer.

An object of the present invention is to provide an apparatus and amethod whereby the pliability of tobacco strands being supplied to acigarette-making machine can readily and easilybe increased.

According to the invention, a stream of tobacco strands carried in astream of air is subjected to microwave-radiation energy by passing itthrough a radiation chamber. Suitably, the microwaves may be of awavelength in the range from to 100 cms. Such waves may be directed tothe radiation chamber by an accurately formed wave-guide. Preferably,the stream of air carrying the tobacco strands is directed through thechamber at a substantial distance from walls where the energy level islow, and is guided in a desired path by delimiting walls of materialtransparent to microwave energy, for example polypropylene. If desired,an agitator in the form of a fan may be used within the radiationchamber. Filter means may be provided at the chamber inlet and outletfor the stream of tobacco strands to ensure that the microwave energy iscompletely retained within the radiation chamber.

By such treatment, the pliability of the tobacco strands can beincreased, so reducing the losses of tobacco as dust during processing.The tobacco strands may have increased filling power and the cigarettesproduced therefrom may have a moisture content at or near the optimumvalue for packing procedures.

One manner of carrying the invention into effect, by way of example,will now be more fully described with reference to the accompanyingdrawings, in which:

FIG. 1 is a substantially vertical section (on the line l-I in FIG. 2)through a suitable form of radiation chamber and associatedtobacco-conveying means,

FIG. 2 a side elevation, of the chamber alone, broken away in places todisclose underlying parts, and

FIG. 3 a transverse section on the line III-III in FIG. 2.

The radiation chamber illustrated comprises a box 1 of nearly squaretrapezium shape in side elevation (FIG. 2) and of elongated rectangularshape in vertical and transverse sections (FIGS. 1 and 3). The chamberis composed of walls 2, 3, 4, 5, of radiation-impervious material,secured tightly together, with seals at 6. The radiation is supplied tothe chamber 1 from a source of high frequency energy 7 through a guide 8leading to an opening 9 in the large wall 2 so located that thedistribution of energy is substantially transversely uniform as ittraverses the chamber. If desired, however, energy may be supplied tothe chamber at two or more positions along the tobacco path. Suitably,the source 7 may be a magnetron valve operating at a frequency withinthe microwave band. A fan 10 disposed in the chamber 1 and driven by anexternal electric motor 11 serves to cool the adjacent arcuate wall 12.Walls 12, 13 of propylene plastic material bound a path 14, within thechamber 1, for an air stream carrying the tobacco through the saidchamber. In order to produce a wide,

thin stream of tobacco-carrying air, the path 14 is narrow in verticalsection (FIG. 1), but extends for the full transverse dimension (FIG. 3)of the chamber and from the lower to the upper edge of the wall 3 awayfrom the source 7 of the radiation. In the vertical section, the walls12, 13 are of an arcuate shape, so that the path 14 is of a curved form,convex towards the wall 2, and is spaced away from the walls, 2, 3throughout most of its course. At the ends of the curved path 14, thereare short, substantially straight, upright path sections 15 and I6dimensioned and arranged to serve as microwave retaining filters.

In FIG. I, the radiation chamber 1 is shown mounted in place of aconventional tobacco-conveying arrangement below the moving perforatedcollection band, operating with suction, which leads to knownrod-forming apparatus of a cigarette-making machine. This band moves ina groove 17 in a guide 18 below a slot in the bottom of a suctionchamber 19, tobacco issuing from the path section 16 being carried awayon the underside of the said band. Near its upper edge, the wall 13 isformed with a band of small perforations forming a grille 20 permittingremoval, by way of a perforated-metal filter 21 for microwave energy anda duct 210 FIG. I), of part of the tobacco-conveying air stream justbefore the issuing tobacco arrives at the aforesaid moving, perforated,band of the machine, where its conveyance is taken over by the latter.

The cut cigarette tobacco may be supplied to the lower end of the path14 through the chamber 1 by known tobacco-feeding means. As illustratedin FIG. 1, tobacco furnished by rolls 22,23 is fed by a toothed roll 24as an even thin layer 25 to the outer surface of a rotating gauze drum26 whose interior is subject to suction by way of a duct 27. The effectof the suction in causing adherence of the tobacco layer to the drum 26is limited to the bottom arc thereof by stationary masking pieces 28inside the drum, the tobacco being released as it approaches thepath-section 1 5. Air flows in from below as indicated by the arrows 29and part of this air entrains the tobacco and conveys it through thepath 14. A series of fixed vanes 30 assists in guiding the tobacco.

The following is an example of the treatment of cigarette tobacco, usingthe above-described radiation chamber, the path 14 having a length ofabout 53 cms., a width of about 58 cms. and a thickness of about 0.8cms.

Strands of Virginia flue-cured tobacco cut at 55 cuts per inch and witha moisture content of 13.75 percent were fed to the path 14 through thechamber 1 at a rate of 5 lbs/minute. Microwave radiation energy wassupplied from the source 7 at a rate of 1.5 KW. The rate of air flowthrough the path 14 was approximately 120 cu.ft./min. up to the grille20, and, as part of the air issues through the duct 21a, approximately40 cu.ft./min. from that point to the chamber 19. The temperature of theair in the path 14 was F., but as microwave energy generates heat frominside the tobacco the air temperature was not a measure of thetemperature of the tobacco.

This treatment reduced the moisture content of the tobacco by about 0.75percent, The cigarettes produced from the tobacco had a moisture contentsuitable for packing and pliability that avoided excessive degradationof the tobacco strands in the rod-forming process in the machine.

I claim:

1. A microwave apparatus mounted on a cigarette-making machine fortreatment of cut tobacco comprising: means providing a radiation chamberhaving inlet and outlet openings for tobacco strands at opposite endsthereof formed therein and a pair of confronting arcuate wallspositioned in spaced relation to each other and formed of a materialtransparent to microwave energy, said walls being mounted in the chamberto the inlet and outlet openings at their respective ends so as todefine a path for passing a stream of tobacco strands means providingstream of air for carrying said tobacco stream therethrough; means forgenerating microwave radiation energy mounted to the chamber and meansfor directing the radiation energy into and through the radiationchamber whereby the tobacco between said walls is subjected to radiationenergy which renders the tobacco strands more pliable.

2. The apparatus according to claim 1 wherein the means for generatingmicrowave energy produces a wave length of microwave energy in the rangeof from to 100 cms.

3. The apparatus according to claim 1 wherein the walls defining thepath for passing the stream of tobacco strands carried on a stream ofair through the chamber is disposed in the radiation chamber at adistance remote from a microwave generating means.

4. The apparatus according to claim 1 wherein the walls defining saidpath for passing said stream of tobacco strands carried on said streamof air through said chamber extend across the chamber, the walls beingconvex with respect to the side of the chamber from which the microwavegenerating means is mounted.

5. The apparatus of claim 1 wherein a fan is mounted within theradiation chamber so that portions of the fan lie within the path of themicrowave generating means.

6. The apparatus of claim 1 wherein the radiation chamber has mountedadjacent the inlet and outlet openings microwave filter means for thestream of tobacco-carrying air in order to retain the microwave energywithin the chamber.

7. A method of treating cut tobacco in a cigaretteqnaking machinecomprising: passing a stream of tobacco strands carried in a stream ofair into and through a microwave radiation chamber conducting thetobacco strands along an arcuate path defined by a pair of spacedconfronting walls made of a material transparent to microwave energy,then subjecting the tobacco strands to microwave radiation energy fromsaid source while said tobacco is conducted along said path whereby thetreated tobacco strands are rendered more pliable.

8. A microwave apparatus mounted on a cigarette making machine fortreatment of cut tobacco comprising: a radiation chamber having inletand outlet openings formed therein and a pair of confronting wallspositioned in spaced relation to each other and formed of a materialtransparent to microwave energy, pneumatic and mechanical means forpassing a stream of air and tobacco strands between said walls, saidwalls being mounted in the chamber to the inlet and outlet openings attheir respective ends so as to define a path for passing said streamtherethrough; means for generating microwave radiation energy mounted tothe radiation chamber; means for directing the radiation energy throughthe radiation chamber whereby the tobacco in said stream is subjected toradiation energy which renders the tobacco strands more pliable; saidspaced walls being curved from the inlet opening to the outlet openingsuch that the convex portion of the curve lies toward the side of theradiation chamber from which the microwave energy generating means ismounted.

9. A microwave apparatus mounted on a cigarette-making machine for thetreatment of cut tobacco comprising: a radiation chamber having inletand outlet openings and a pair of confronting walls positioned in spacedrelation to each other and formed of a material transparent to themicrowave energy, pneumatic and mechanical means for passing a stream ofair and tobacco strands between said walls, said walls being mounted inthe chamber to the inlet and outlet openings at their respective ends soas to define a path for passing said stream therethrough; means forgenerating microwave radiation energy mounted to the radiation chamber;and means for directing the radiation energy through the radiationchamber whereby the tobacco is subjected to radiation energy whichrenders the tobacco strands more pliable; microwave filter means mountedto the chamber and positioned adjacent the inlet and outlet openings forthe air and tobacco stream in order to retain microwave energy withinthe radiation chamber.

1. A microwave apparatus mounted on a cigarette-making machine fortreatment of cut tobacco comprising: means providing a radiation chamberhaving inlet and outlet openings for tobacco strands at opposite endsthereof formed therein and a pair of confronting arcuate wallspositioned in spaced relation to each other and formed of a materialtransparent to microwave energy, said walls being mounted in the chamberto the inlet and outlet openings at their respective ends so as todefine a path for passing a stream of tobacco strands means providingstream of air for carrying said tobacco stream therethrough; means forgenerating microwave radiation energy mounted to the chamber and meansfor directing the radiation energy into and through the radiationchamber whereby the tobacco between said walls is subjected to radiationenergy which renders the tobacco strands more pliable.
 2. The apparatusaccording to claim 1 wherein the means for generating microwave energyproduces a wave length of microwave energy in the range of from 10 to100 cms.
 3. The apparatus according to claim 1 wherein the wallsdefining the path for passing the stream of tobacco strands carried on astream of air through the chamber is disposed in the radiation chamberat a distance remote from a microwave generating means.
 4. The apparatusaccording to claim 1 wherein the walls defining said path for passingsaid stream of tobacco strands carried on said stream of air throughsaid chamber extend across the chamber, the walls being convex withrespect to the side of the chamber from which the microwave generatingmeans is mounted.
 5. The apparatus of claim 1 wherein a fan is mountedwithin the radiation chamber so that portions of the fan lie within thepath of the microwave generating means.
 6. The apparatus of claim 1wherein the radiation chamber has mounted adjacent the inlet and outletopenings microwave filter means for the stream of tobacco-carrying airin order to retain the microwave energy within the chamber.
 7. A methodof treating cut tobacco in a cigarette-making machine comprising:passing a stream of tobacco strands carried in a stream of air into andthrough a microwave radiation chamber conducting the tobacco strandsalong an arcuate path defined by a pair of spaced confronting walls madeof a material transparent to microwave energy, theN subjecting thetobacco strands to microwave radiation energy from said source whilesaid tobacco is conducted along said path whereby the treated tobaccostrands are rendered more pliable.
 8. A microwave apparatus mounted on acigarette making machine for treatment of cut tobacco comprising: aradiation chamber having inlet and outlet openings formed therein and apair of confronting walls positioned in spaced relation to each otherand formed of a material transparent to microwave energy, pneumatic andmechanical means for passing a stream of air and tobacco strands betweensaid walls, said walls being mounted in the chamber to the inlet andoutlet openings at their respective ends so as to define a path forpassing said stream therethrough; means for generating microwaveradiation energy mounted to the radiation chamber; means for directingthe radiation energy through the radiation chamber whereby the tobaccoin said stream is subjected to radiation energy which renders thetobacco strands more pliable; said spaced walls being curved from theinlet opening to the outlet opening such that the convex portion of thecurve lies toward the side of the radiation chamber from which themicrowave energy generating means is mounted.
 9. A microwave apparatusmounted on a cigarette-making machine for the treatment of cut tobaccocomprising: a radiation chamber having inlet and outlet openings and apair of confronting walls positioned in spaced relation to each otherand formed of a material transparent to the microwave energy, pneumaticand mechanical means for passing a stream of air and tobacco strandsbetween said walls, said walls being mounted in the chamber to the inletand outlet openings at their respective ends so as to define a path forpassing said stream therethrough; means for generating microwaveradiation energy mounted to the radiation chamber; and means fordirecting the radiation energy through the radiation chamber whereby thetobacco is subjected to radiation energy which renders the tobaccostrands more pliable; microwave filter means mounted to the chamber andpositioned adjacent the inlet and outlet openings for the air andtobacco stream in order to retain microwave energy within the radiationchamber.